1. Field of the Invention
This invention relates to a round baler having side structures, fixed rolls, at least two moveable pivot arms carrying mobile rolls, and an endless flexible bale-forming arrangement and routed over the rolls to create, and encompass, a cylindrical circumference of a bale chamber.
2. Related Technology
European Patent specification EP 309 936 B1 discloses a round baler with a single set of endless belts, which are routed over a series of fixed and mobile rolls, whereas the mobile rolls are carried on two tensioning arms, which create several loops to provide sufficient belt length to extend over the circumference of a completed bale. A lower tensioning arm is applied by a spring, which extends with additional crop entering the bale chamber.
EP A1 309 941 discloses a round baler with two sets of endless belts and two tensioning arms, which are controlled by means of a single hydraulic cylinder. This hydraulic cylinder is used to control the tension in the two sets of belts to provide for controlled movement of the bale during formation and unloading.
EP A1 308 078 discloses a round baler with side structures and mobile as well as fixed rolls. A single tensioning arm is provided in about the center of the bale chamber to create a loop taking up the slack in the belts, when the bale chamber is empty. Another loop is formed by an unloading pivot frame, when it is moved to an unloading position.
EP A1 308 079 teaches a round baler with side structures and mobile and fixed rolls. A single tensioning arm is provided in the front area of the round baler to release more or less of a loop of the belts to the circumference of a growing bale. A tensioning roll acts on the belts. The tensioning arm is provided with a pair of parallel rolls, which guide two strands of the belts and limit the bale chamber in its upper region. Another loop is formed by an unloading pivot frame, when it is moved to an unloading position.
The problem this invention is based on is seen in the challenges of forming bales with a bigger diameter, such as two meters or greater, whereas belts, chains or the like and their control means should be kept at a minimum to keep costs low.